UK-based aerospace company Reaction Engines Limited (REL) has announced substantial new investments from key companies into its part-jet, part-rocket engine. The project could change the future of both space launch systems and hypersonic travel within the atmosphere. The new investments, from Boeing and Rolls-Royce, total £26.5 million, bringing the total capital raised in the last three years to £100m, which includes £60 million from the British government.

“Rolls-Royce and Boeing – these are really big names, and it’s fantastic to be in this position. Rolls are super-positive about the technology. They want us to be independent and innovative, and to push our technology as hard as possible. And Boeing – that’s amazing. They are the world’s biggest aerospace company, have decades of expertise and future plans that, for us I’m sure, will be really exciting.”

The project, called the Sabre engine, could launch spacecraft from the ground into orbit with just a single step. Through Mach 5.5, which is 5.5 times the speed of sound, it would operate as a traditional jet engine. Above this threshold, it would operate in its rocket mode.

One key technology making the Sabre engine possible is a compact pre-cooler heat-exchanger developed by REL, which can cool incoming air as hot as 1,000C down to -150C in under 1/100th of a second. This allows the engine to utilize oxygen directly from the atmosphere for combustion, without the need for heavy onboard oxygen tanks.

While such an engine could be used for an orbiting spaceplane, it could also allow for high-speed travel within the Earth’s atmosphere – a concept of great interest to Boeing. Steve Nordlund, Vice President of HorizonX, Boeing’s investment division, said:

“As Reaction Engines unlocks advanced propulsion that could change the future of air and space travel, we expect to leverage their revolutionary technology to support Boeing’s pursuit of hypersonic flight.”

Rolls Royce, which has worked with REL on precursors to the Sabre project, said the company is “delighted to become a strategic investor in Reaction Engines Limited, an innovative UK company that is helping push the boundaries of aviation technology,” in a statement from the company’s CTO, Paul Stein.

REL will demonstrate aspects of its project in the coming years. This summer, under contract with the US Defense Advanced Research Projects Agency (DARPA), the company will test its pre-cooler technology in conditions that will simulate the hot airstreams vehicles face when traveling at hypersonic speeds.

In 2020, the company will demonstrate the Sabre’s full cycle at a new test facility at Westcott, in Buckinghamshire, in the UK. If this goes as planned, the next step will be to test the engine on a flight vehicle.